Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/015—Ink jet characterised by the jet generation process
  • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
  • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
  • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
  • B41J2/04596—Non-ejecting pulses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/015—Ink jet characterised by the jet generation process
  • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
  • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
  • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
  • B41J2/04581—Control methods or devices therefor, e.g. driver circuits, control circuits controlling heads based on piezoelectric elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/015—Ink jet characterised by the jet generation process
  • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
  • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
  • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
  • B41J2/04588—Control methods or devices therefor, e.g. driver circuits, control circuits using a specific waveform

Definitions

• the present invention relates to a droplet deposition apparatus. It may find particularly beneficial application in a printer, such as an inkjet printer.
• Droplet deposition apparatuses such as inkjet printers are known to provide controlled ejection of droplets from a droplet deposition head, and to provide for controlled placement of such droplets to create dots on a receiving or print medium .
• Droplet deposition heads such as inkjet printheads generally comprise one or more pressure chambers each having associated ejection mechanisms in the form of actuator elements.
• the actuator elements are configured to deform in a controlled manner in response to a signal, e.g. a waveform comprising one or more drive pulses, thereby causing droplets to be generated and ejected from nozzles associated with the respective one or more pressure chambers.
• a signal e.g. a waveform comprising one or more drive pulses
• the actuator elements may be provided in different configurations depending on the specific application. For example, the actuator elements may be provided in roof mode or shared wall configurations.
• Embodiments may provide improved droplet deposition apparatuses, droplet deposition heads, or methods of driving such heads.
• a drive circuit for a droplet deposition apparatus configured to generate a drive waveform having a drive pulse, a first non-ejection pulse and a second non-ejection pulse, and wherein the first non-ejection pulse is inverted with respect to the second non-ejection pulse.
• a method of driving an actuator element with a drive waveform to eject droplets from an associated pressure chamber comprising : applying a drive pulse to the actuator element; applying a first non-ejection pulse to the actuator element; applying a second non-ejection pulse to the actuator element, wherein the second non-ejection pulse is inverted with respect to the first non-ejection pulse.
• Figure 1 schematically shows a cross section of a part of a droplet deposition head according to an embodiment
• Figure 2a schematically shows an example of a known drive waveform having a single drive pulse
• Figure 2b schematically shows, by example only, the effect the drive pulse of Figure 2a has on a membrane when applied to an actuator element associated with the membrane;
• Figure 3a schematically shows a representation of the drive waveform of
• Figure 3b schematically graphically shows a signal resulting from the waveform of Figure 3a at an actuator element, superimposed in time on the measured pressure in an associated pressure chamber in response to the actual signal;
• Figure 3c graphically represents the result of driving a droplet deposition head with the waveform in figure 3a;
• Figure 4 schematically shows a drive waveform according to an embodiment
• Figure 5a schematically shows a representation of the drive waveform of
• Figure 5b graphically shows a signal resulting from the waveform of Figure 5a at an actuator element, superimposed in time on the measured pressure in an associated pressure chamber in response to the actual signal;
• Figure 5c graphically represents the result of driving a droplet deposition head with the waveform in figure 5a;
• Figure 6a graphically represents a standard deviation in frequency spectra for velocity and volume as a function of the delay between the cancellation pulse and the calming pulse in the drive waveform of Figure 4;
• Figure 6b graphically represents a standard deviation in frequency spectra for velocity and volume as a function of the amplitude of the calming pulse and the drive pulse in the drive waveform of Figure 4;
• Figure 6c graphically represents a standard deviation in frequency spectra for velocity as a function of the delay between the cancellation pulse and the drive pulse in the drive waveform of Figure 4;
• Figure 7 schematically shows a drive waveform according to a further embodiment
• Figures 8a-8d schematically show a drive pulse according to a further embodiment
• Figure 9 schematically shows an example of a droplet deposition apparatus having a circuit for generating a drive waveform according to an embodiment.
• Figure 1 schematically shows a cross section of part of a droplet deposition head 1 of a droplet deposition apparatus according to an embodiment.
• the droplet deposition head 1 comprises at least one pressure chamber 2 having a membrane 3 with an actuator element 4 provided thereon to effect movement of the membrane 3 between a first position (depicted as PI), here shown as a neutral position, inwards into the pressure chamber to a second position (depicted as P2).
• PI first position
• P2 second position
• the actuator element could also be arranged to deflect the membrane in a direction from PI opposite to that of P2 (i.e. outwards of the pressure chamber).
• the actuator element 4 is depicted as being located on the membrane 3 forming a wall of the pressure chamber 2 that faces a nozzle 12 provided on a bottom wall of the pressure chamber 2 opposite the membrane 3.
• the actuator element 4 may be arranged elsewhere within the pressure chamber 4 and in fluid communication with the nozzle, e.g. via a descender, or so as to form the side walls in a bulk piezoelectric actuator.
• the pressure chamber 2 comprises a fluidic inlet port 14 for receiving fluid from a reservoir 16 arranged in fluidic communication with the pressure chamber 2.
• the reservoir 16 is merely depicted adjacent the pressure chamber 2 for illustrative purposes. It could for example be provided further upstream, or remote from the droplet deposition head using a series of pumps/valves as appropriate.
• the pressure chamber 2 optionally comprises a fluidic outlet port 18 for recycling any excess fluid in the pressure chamber 2 back to the reservoir 16 (or to another destination).
• a fluidic outlet port 18 for recycling any excess fluid in the pressure chamber 2 back to the reservoir 16 (or to another destination).
• the fluidic outlet port 18 may merely replenish fluid that has been ejected from the pressure chamber 2 via the nozzle 12.
• the fluidic inlet port 14 and/or fluidic outlet port 18 may comprise a one-way valve.
• the actuator element 4 is depicted as a piezoelectric actuator element 4 whereby a thin film of piezoelectric material 6 is provided between a first electrode 8 and a second electrode 10 such that applying an electric field across the actuator element 4 causes the actuator element 4 to charge, such that it experiences a strain and deforms. It will be understood that any suitable actuator element 4 may be used instead of a piezoelectric actuator element.
• the pressure chamber 2 is arranged in what is commonly referred to as a "roof-mode" configuration, whereby deflection of the membrane 3 changes the volume, and, therefore the pressure, within the pressure chamber 2 such that droplets are ejected from the nozzle 12 due to the resulting pressure change.
• Such deformation may be achieved by applying a drive waveform having one or more drive pulses to the actuator element 4 e.g. by selectively applying one or more drive pulses in the drive waveform to the first electrode 8, whilst maintaining the bottom electrode 10 at a reference potential such as ground potential.
• the pressure change causes a pressure wave that reflects off the boundary structures, such as the bounding surfaces/walls of the pressure chamber, and causes residual pressure waves in the pressure chamber that are typically undesirable and impact the properties of subsequently ejected droplets, and therefore impact the achievable print quality of the droplet deposition apparatus.
• the residual pressure waves may result in either constructive interference or destructive interference with pressure waves caused by following drive pulses, which may lead to a resulting droplet being ejected either faster or slower than it would otherwise be.
• constructive interference may increase the effective amplitude of a following drive pulse, thereby increasing droplet velocity of the resulting droplet
• destructive interference may decrease the effective amplitude of a following drive pulse thereby decreasing droplet velocity of the resulting droplet.
• the interference may also affect the drop volume of such droplets.
• droplet deposition head 1 may be fabricated using any suitable fabrication processes or techniques, such as, micro-electrical-mechanical systems (MEMS) processes.
• MEMS micro-electrical-mechanical systems
• pressure chamber 2 may be spaced along a linear array or may be staggered relative to each other.
• Figure 2a schematically shows an example of a known drive waveform 20 having a single drive pulse 22.
• the drive pulse 22 comprises an amplitude (Vm), having a first voltage level Vdhve and a second voltage level West.
• the drive pulse 22 comprises a falling portion whereby a leading edge falls from the drive voltage (Vdhve) to the rest voltage (West) .
• the drive pulse 22 also comprises a rising portion whereby, after a time period defined by the pulse width (PW), a trailing edge of the drive pulse 22 rises from Vrest to Vd rive.
• PW pulse width
• the drive pulse 22 may be applied to one or more actuator elements, thereby deforming the membrane 3 sufficiently to draw fluid into the pressure chamber and to eject a droplet from a corresponding nozzle (not shown).
• FIGs 2b (i)-(iii) schematically shows, by example only, the effect the drive pulse 22 has on membrane 3 when applied to an actuator element associated with the membrane 3.
• the membrane 3 is deformed. As the leading edge is applied, the membrane 3 changes from being in a deformed state to a state as defined by Vrest, thereby creating a negative pressure in the pressure chamber and drawing in fluid thereto.
• the resulting droplets may be controlled to accurately land on a receiving medium (in conjunction with controlling a motion of a receiving medium, where necessary) within predetermined areas defined as pixels.
• each pixel will be filled with either one or no droplet.
• greyscale levels may be added by printing more than one droplet into each pixel to alter the perceived density of the image pixel.
• the droplets landing within the same pixel will generally be referred to as sub-droplets.
• such sub-droplets may be ejected in rapid succession so as to merge or coalesce before landing on the receiving medium as one droplet of a volume that is the sum of all sub-droplet volumes.
• the droplet Once landed on the receiving medium, the droplet will in the following text be referred to as a 'dot'; this dot will have a colour density defined by the sum of all sub-droplet volumes.
• a greyscale level of 0,l,2,3,...,n is intended to correspond to 0,l,2,3,...,n ejected sub-droplets into the same pixel, where the volume of each sub-droplet contributes to the total volume landing in the pixel and therefore to the colour density of the resulting dot.
• Figure 3a schematically shows a representation of the drive waveform 20 when applied to an actuator element
• Figure 3b schematically shows the actual signal resulting from the drive waveform 20 at the actuator element (dashed line), superimposed in time on the measured pressure (solid line) in an associated pressure chamber in response to the actual signal
• Figure 3c graphically represents the result of driving a droplet deposition head with the waveform in figure 3a i.e. the droplet velocity (m/s) 26a and droplet volume (pico-litres (pi)) 26b as a function of jetting frequency (kHz).
• the period between consecutive drive pulses 22 in the waveform 20 may be increased to allow the residual pressure waves to decay sufficiently to avoid interference with pressure waves caused by a subsequent drive pulse 22.
• the delay between consecutive drive pulses 22 is reduced whereby the residual pressure waves in the pressure chamber may not decay sufficiently to avoid interference, as is evident above approximately 30kHz in the illustrative example of Figure 3c, below which the droplet velocity (m/s) 26a and droplet volume (pi) 26b are substantially constant.
• the achievable print quality of a particular nozzle may be measured against a number of parameters including, but not limited to droplet velocity and droplet volume. Therefore, the interference above approximately 30kHz may negatively affect the achievable print quality of the droplet deposition apparatus.
• additional non-ejection pulses are provided in the drive waveform and applied to an actuator element to reduce or minimise the residual pressure waves in the associated pressure chamber, whereby the additional non-ejection pulses reduce the effects of interference to achieve predictable and uniform droplet ejection properties, and therefore, to achieve improved print quality over a wider range of frequencies.
• Figure 4 schematically shows a drive waveform 30 having a drive pulse 32 and additional non-ejection pulses 34 and 36 according to an embodiment.
• the drive pulse 32 may be applied to an actuator element to generate one or more pressure waves which cause ejection of a droplet from an associated nozzle.
• the first non-ejection pulse 34 is applied to the actuator element after the drive pulse to generate one or more pressure waves which destructively interfere with the residual pressure waves resulting from the drive pulse 32.
• the second non-ejection pulse 36 is applied to the actuator element after the cancellation pulse to generate one or more pressure waves which destructively interfere with the residual pressure waves resulting from the drive pulse 32 and cancellation pulse 34, such that the residual pressure waves in the pressure chamber decay faster in comparison to when only the drive pulse is applied (as was described above and illustrated at Figures 2a-3c above).
• the drive pulse 32 comprises an amplitude
• the drive pulse 32 further comprises a pulse width (OPW).
• the cancellation pulse 34 follows the drive pulse 32 in the drive waveform 30 after a delay (CaG) (where CaG > 0), the cancellation pulse 34 having an amplitude (Vca) and pulse width (CaW).
• the cancellation pulse 34 is non-inverted with respect to the drive pulse 32.
• the calming pulse 36 follows the cancellation pulse 34 in the drive waveform 30 after a delay (CmG) (where CmG > 0), the calming pulse 36 having an amplitude (Vcm) and pulse width (CmW).
• the calming pulse 36 is inverted with respect to the cancellation pulse 34, and, in the present embodiment, is inverted with respect to the drive pulse 32.
• the characteristics of the drive waveform 30 can be varied to affect the generated droplets in different ways.
• parameter values of the respective pulse widths (OPW, CaW & CmW); respective amplitudes (Vm, Vca, &Vcm); and respective delays (CaG & CmG) associated with the different pulses may be varied to achieve different droplet velocities and droplet volumes.
• parameter values for the waveform, normalised against OPW are substantially as follows: ⁇ OPW/HP (Helmholtz period of the pressure chamber) is substantially equal to ( «) 0.5
• Figure 5a schematically shows a representation of the drive waveform 30 when applied to an actuator element
• Figure 5b schematically shows the actual signal resulting from the drive waveform 30 at the actuator element (dashed line), superimposed in time on the measured pressure in an associated pressure chamber (solid line) in response to the actual signal
• Figure 5c graphically represents the result of driving a droplet deposition head with the waveform in Figure 5a, i.e. the droplet velocity (m/s) 40a and droplet volume (pico-litres (pi)) 40b as a function of jetting frequency (kHz).
• the delay between a calming pulse and a following drive pulse may be reduced in comparison to the delay required between consecutive drive pulses when a cancellation pulse and calming pulse are not applied which may provide for more uniform output at higher print frequencies, thereby providing improved print quality at higher print frequencies.
• Figure 6a graphically represents the standard deviation in the frequency spectra for droplet velocity 42 and droplet volume 44 as a function of the delay (CmG) between the cancellation pulse and calming pulse with respect to OPW (CmG/OPW);
• Figure 6b graphically represents the standard deviation in the frequency spectra for droplet velocity 42 and droplet volume 44 as a function of the amplitude Vcm with respect to Vm (Vcm/Vm),
• Figure 6c graphically represents a standard deviation in frequency spectra for velocity 42 as a function of the delay (CaG) between the cancellation pulse (CaW) and the drive pulse (OPW) in the drive waveform of Figure 4.
• a preferable range for (CmG/OPW) is 0 ⁇ CmG/OPW) ⁇ 0.55; and a more preferable range is 0.2 ⁇ (CmG/OPW) ⁇ 0.45; and an even further preferable range is 0.3 ⁇ (CmG/OPW) ⁇ 0.4.
• the parameter values of the drive waveform 30 as set out above in relation to Figure 4 were maintained substantially constant but whereby Vcm was swept/varied.
• a preferable range for (Vcm/Vm) is 0 ⁇ (Vcm/Vm) ⁇ 0.65; and a more preferable range is 0.1 ⁇ (Vcm/Vm) ⁇ 0.55, and an even further preferable range is 0.25 ⁇ (Vcm/Vm) ⁇ 0.5.
• a preferable range for (CaG/OPW) is 0.44 ⁇ (CaG/OPW) ⁇ 0.59 and a more preferable range is 0.47 ⁇ (CaG/OPW) ⁇ 0.52, and an even further preferable range is 0.49 ⁇ (CaG/OPW) ⁇ 0.51.
• the OPW « 0.5HP In the embodiments above, the OPW « 0.5HP. In other examples the optimum pulse width of the drive pulse is in the range 0.25 ⁇ OPW/HP ⁇ 0.75.
• Vca ⁇ Vm .
• the amplitude Vca may be increased or decreased with respect to Vm, and a preferable range is 0.65 ⁇ (Vca/Vm) ⁇ 1.35, and a more preferable range is 0.8 ⁇ (Vca/Vm) ⁇ 1.2, and a more preferable range is 0.9 ⁇ (Vca/Vm) ⁇ 1.1.
• a preferable range for (CmW/OPW) is 0.2 ⁇ (CaG/OPW) ⁇ 0.4.
• a preferable range for (CmW/OPW) is 0.25 ⁇ (CmW/OPW) ⁇ 0.75, and a more preferable range is 0.3 ⁇ (CmW/OPW) ⁇ 0.6.
• the frequency responses of the drop velocity and drop volume may be less favourable, although such frequency responses may be more preferable in comparison to applying a drive pulse in isolation.
• the cancellation pulses and calming pulses reduce the pressure waves in the pressure chamber. It will be understood by a person skilled in that art that applying the cancellation pulse and calming pulse after a drive pulse may also reduce the impact of such pressure waves on neighbouring pressure chambers, thereby reducing the effects of cross-talk in the droplet deposition head.
• greyscale levels may be achieved by using two or more drive pulses to eject a corresponding sub-droplet whereby, in embodiments, the two or more drive pulses are followed by a cancellation pulse and a calming pulse.
• the drive waveform may comprise a drive pulse and a calming pulse, which is, as above, inverted with respect to the drive pulse and whereby the drive waveform does not include a cancellation pulse between the drive pulse and the calming pulse. Whilst such an embodiment may reduce the time it takes for pressures waves within the pressure chamber to decay, Vcm is required to be increased to achieve such a decay in comparison to when a cancellation pulse is provided between the drive pulse and calming pulse.
• characteristics of the drive and non-ejection pulses may be modified. Such characteristics include but are not limited to: amplitude, pulse width, slew rates and/or intermediate voltages. For pulses such as trapezoidal shaped pulses having different slew rates, the pulse width may, for consistency, be measured at, for example, half the amplitude of the pulse.
• drive pulses are not limited to the substantially square shape depicted in Figure 2a, 3a and 5a, and any suitable shapes may be used to eject droplets as required. For example, trapezoidal, rectangular or sinusoid shaped (e.g. symmetric sinusoid) drive pulses may be used.
• Figure 7 shows a further illustrative example of a drive waveform 50 having a symmetric sinusoid drive pulse 52 and additional non-ejection pulses, such as cancellation pulse 54 and calming pulse 56 according to a further embodiment.
• the symmetric sinusoid drive pulse 52 is in two parts, a first drive part 58a and a second drive part 58b.
• a delay (not shown) may be provided between the first drive part 58a and second drive part 58b.
• the cancellation pulse 54 is inverted with respect to the calming pulse 56 to provide the advantages as previously described.
• OPW is taken to be that of the second drive part 58b, whilst the amplitude Vca of the cancellation pulse is substantially equal to the amplitude Vm 2 of the second drive part 58b.
• the shape of the drive, cancellation and calming pulses may be modified so as to affect the characteristics of the droplets, pressure waves or the residual pressure waves.
• the pulses maybe "trimmed" to provide one or more ledges within the pulse so as to, for the drive pulses, generate droplets having certain characteristics or, for the non-ejection pulses, to affect the residual pressure waves within the pressure chamber.
• the length of the ledge portion 62 may be modified as required by a specific application (e.g. as depicted by NW1 and NW2 in Figures 8a and 8b respectively). Additionally, or alternatively, the height of the ledge portion 62 may be modified as required by a specific application (e.g. as depicted by NH 1 and NH2 in Figures 8c and 8d respectively). It will be understood that a ledge may additionally or alternatively be provided on the leading edge of the drive pulse 62.
• a drive pulse and the cancellation pulse may be independently trimmed so that the effective amplitudes match or do not match.
• the peak voltage for trimmed drive pulses may not match the peak voltage of the trimmed cancellation pulse yet have the same result as if the peak voltages were equal.
• the drive waveform may be generated using any suitable circuitry.
• the drive circuit may generate a common drive waveform which is selectively applied to one or more actuator elements.
• the drive circuit may generate a drive waveform per actuator element.
• Figure 9 schematically shows an example of a droplet deposition apparatus 70 having circuitry for generating a drive waveform having a drive pulse, a first non-ejection pulse and a second non-ejection pulse, wherein the drive waveform is selectively applied to one or more actuator elements.
• the droplet deposition apparatus 70 may comprise a plurality of ' ⁇ ' actuator elements 4 (where ' ⁇ ' is an integer), for ejecting droplets in a controlled manner from nozzles associated therewith .
• ' ⁇ ' is an integer
• the droplet deposition apparatus has a system circuit 72 which includes communication circuitry 74 for transmitting/receiving communications to/from one or more external sources 76, depicted as a host computer in Figure 9.
• the system circuit 72 further comprises a system control unit 78, which comprises processing logic to process data (e.g. image data, programs, instructions received from a user etc.) and generate output signals in response to the processed data.
• the system control unit 78 may comprise any suitable circuitry or logic, and may, for example, be a field programmable gate array (FPGA), system on chip device, microprocessor, microcontroller or one or more integrated circuits.
• FPGA field programmable gate array
• image data sent from the host computer 76 is received at the system control unit 78 and processed thereat.
• the image data relates to the desired characteristics of a printed dot to be created within a pixel on a receiving medium (e.g. pixel position, density, colour etc.), where the pixel defines a specific position within a rasterised version of the image.
• the image data may define the characteristics of the droplets required to be ejected from a particular nozzle to create the dot in the pixel.
• the system circuit 72 includes drive circuit 80 configured to generate a drive waveform having a drive pulse, a first non-ejection pulse and a second non- ejection pulse wherein the first non-ejection pulse is inverted with respect to the second non-ejection pulse.
• the drive circuit 80 generates the drive waveform in response to a waveform-control signal 82 from the control unit 78, whereby the waveform-control signal 82 comprises a logic output which is fed to a digital-to-analog converter (DAC) 83, whereby an analog output from the DAC 83 is fed to an amplifier 84 for generating the drive waveform.
• DAC digital-to-analog converter
• control unit 78 generates the waveform- control signal 82 in response to, for example, the image data, programs, instructions received from a user etc., whereby the waveform-control signal 82 defines the characteristics of the drive waveform and the pulses thereof (e.g. shapes, amplitudes, pulse widths, delays between pulses etc.).
• the drive waveform is transmitted to head-drive circuit 85, along one or more transmission paths 86 so as to be selectively applied to the one or more actuator elements 4.
• the one or more actuator elements 4 are also connected to one or more return paths 88.
• head-drive circuit 85 comprises an application specific integrated circuit (ASIC), which includes switch logic 90 associated with the one or more actuator elements 4.
• ASIC application specific integrated circuit
• the switch logic 90 is configured to, dependent on the state thereof, pass the drive waveform therethrough in a controllable manner such that the drive waveform can be selectively applied to an associated actuator element 4.
• the switch-logic 90 may be in a closed state to allow the drive waveform to pass therethrough to be applied to the associated actuator element 4, or the switch logic 90 may be in an open state to prevent the drive waveform passing therethrough.
• the switch logic 90 may comprise one or more transistors arranged in a suitable configuration, such as a pass gate configuration.
• the state of the switch logic 90 is controllable by a switch logic-control unit 92 in response to a pixel control signal 94 received from the system control unit 78, whereby the pixel-control signal 94 comprises data defining when the switch logic control unit 92 should control the state of the switch logic 90 so as to apply the drive waveform to the respective actuator elements 4.
• FIG. 9 is an illustrative example of circuitry for generating one or more drive waveforms having a drive pulse, a first non-ejection pulse and a second non-ejection pulse, wherein the first non-ejection pulse is inverted with respect to the second non-ejection pulse.
• any suitable circuitry may be used to generate such drive waveforms.
• the preferred embodiment of the present techniques may be realized in the form of a data carrier having functional data thereon, said functional data comprising functional computer data structures to, when loaded into a computer system or network and operated upon thereby, enable said computer system to perform all the steps of the method.

Landscapes

• Particle Formation And Scattering Control In Inkjet Printers (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=56891355

Family Applications (1)

Country Status (6)

Families Citing this family (3)

Citations (4)

Family Cites Families (14)

• 2016
  • 2016-06-30 GB GB1611489.4A patent/GB2551821B/en active Active
• 2017
  • 2017-06-29 US US16/314,268 patent/US10744764B2/en active Active
  • 2017-06-29 EP EP17736728.1A patent/EP3478505B1/de active Active
  • 2017-06-29 CN CN201780041163.6A patent/CN109414930B/zh active Active
  • 2017-06-29 WO PCT/GB2017/051906 patent/WO2018002630A1/en unknown
• 2018
  • 2018-12-20 IL IL263865A patent/IL263865A/en unknown

Patent Citations (4)

Also Published As

Similar Documents

Legal Events